Cleaning & Corrosion

Question 1

Which of the following is an acceptable first step procedure to help prevent scratching when cleaning a transparent plastic surface?

Answer 1

Flush the surface with clean water

Question 2

When an anodized surface coating is damaged in serviced, it can be partially restored by

Answer 2

Chemical surface treatment

Question 3

What should be done to prevent rapid deterioration when oil or grease come in contact with a tire?

Answer 3

Wipe the tire with a dry cloth followed by a wash down and rinse with soap and water.

Question 4

Which of the following are acceptable to use in cleaning anodized surfaces?

1) steel wool
2) Brass wire brush
3) Aluminum wool
4) Stainless steel wire brush
5) fiber bristle brush

Answer 4

3&5

Question 5

One way of obtaining increased resistance to stress corrosion cracking is by

Answer 5

Creating compressive stresses (via shot peening) on the metal surface

Question 6

Which of the following may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures?

Answer 6

Intergranular corrosion

Question 7

Which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft?

1) Synthetic fiber wiping cloths when using a flammable agent.
2) Cotton giber wiping cloths when using a flammable agent.
3) Atomizing spray equipment.

Answer 7

2 and 3

Question 8

A primary reason why ordinary or otherwise non approved cleaning compounds should not be used when washing aircraft is because their use can result in

Answer 8

Hydrogen embrittlement in metal structures

Question 9

Nickel-cadmium battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of

Answer 9

Boric acid

Question 10

Which of these materials is the most anodic

Answer 10

Magnesium

Question 11

Why is it important not to rotate the crankshaft after the corrosion preventive mixture has been put into the cylinders on engines prepared for storage?

Answer 11

The seal of corrosion preventive mixture will be broken

Question 12

Which of the following are desired effects of using alodine on aluminum alloy?

1) A slightly rough surface
2) Relieved surface stresses
3) A smooth painting surface
4) Increased corrosion resistance

Answer 12

1 and 4

Question 13

Select the solvent used to clean acrylics and rubber

Answer 13

Aliphatic naptha

Question 14

A primary cause of intergranular corrosion is

Answer 14

Improper heat treatment

Question 15

Spilled mercury on aluminum

Answer 15

Cause rapid and server corrosion that is very difficult to control

Question 16

Select the solvent recommended for wipe down of cleaned surfaces just before painting

Answer 16

Aliphatic naptha

Question 17

Which of the listed conditions is NOT one of the requirements for corrosion to occur?

Answer 17

The presence of a passive oxide film.

Question 18

The lifting or flaking of the metal at the surface due to delamination of grain boundaries caused by the pressure of corrosion residual product buildup is called

Answer 18

Exfoliation

Question 19

Corrosion caused by galvanic action is the result of

Answer 19

Contact between two unlike metals

Question 20

For which of the following reasons would a water break test be conducted?

Answer 20

To make certain that bare metal surface is thoroughly clean

Question 21

Corrosion should be removed from magnesium parts with a

Answer 21

Stiff, nonmetallic brush

Question 22

Fretting corrosion is most likely to occur

Answer 22

When two surfaces fit tightly together but can move relative to one another.

Question 23

1) In the corrosion process, it is the cathodic area of dissimilar cathodic material that corrodes.
2) In the galvanic or electro-chemical series for metals, the most anodic metals or those that will give up electrons most easily.
Regarding the above statements,

Answer 23

only no.2 is true.

Question 24

Of the following, when and/or where is galvanic corrosion is most likely to occur?

Answer 24

At the interface of a steel fastener and aluminum alloy inspection plate in the presence of an electrolyte

Question 25

Galvanic corrosion is likely to be most rapid and sever when

Answer 25

The surface area of the anodic metal is smaller than the surface area of the cathodic metal.

Question 26

A nonelectrolytic chemical treatment for aluminum alloys to increase corrosion resistance and paint bonding qualities is called

Answer 26

Alodizing

Question 27

The rust or corrosion that occurs with most metals is the result of

Answer 27

A tendency for them to return to their natural state.

Question 28

Fayed surfaces cause concern in chemical cleaning because of the danger of

Answer 28

Entrapping corrosive materials.

Question 29

How many magnesium engine parts be cleanes?

Answer 29

Wash with a commercial solvent, decarbonize, and scrape or grit blast.

Question 30

Caustic cleaning products used on aluminum structures have the effect of producing

Answer 30

Corrosion

Question 31

Intergranular corrosion in aluminum alloy parts

Answer 31

Cannot always be detected by surface indications.

Question 32

Which of these materials is the most cathodic?

Answer 32

Stainless steel

Question 33

What may be used to remove corrosion from highly stressed steel surfaces?

Answer 33

Fine grit aluminum oxide

Question 34

The interior surface if sealed structural steel tubing would be best protected against corrosion by which of the following?

Answer 34

A coating of linseed oil.